wagtail/client/scss/components/_comments-notification-dropdown.scss

.comment-notifications-toggle-button {
    $root: &;
    padding: 0 17px;
    margin: 0;
    display: flex;
    align-items: center;
    border: 0;
    background-color: transparent;

    &--active,
    &:hover {
        #{$root}__icon {
            color: $color-white;
        }
    }

    &--icon-toggle {
        #{$root}__icon {
            transform: rotate(180deg) translate3d(3px, 10px, 0);
        }
    }

    &__icon {
        width: 15px;
        height: 18px;
        color: $color-teal-dark;
        transition: color 100ms cubic-bezier(0.4, 0, 0.2, 1);
    }
}

.comment-notifications-dropdown {
    position: absolute;
    display: none;
    bottom: -92px;
    z-index: 51;
    background-color: $color-text-base;
    padding: 20px;
    border-radius: 6px;
    min-width: 260px;
    box-sizing: border-box;
    border: 1px solid $color-text-base;

    &__title {
        font-size: 12px;
        text-transform: uppercase;
        font-weight: 700;
        color: $color-white;
    }

    &--active {
        display: block;
    }

    &::before {
        content: '';
        position: absolute;
        top: -8px;
        width: 0;
        height: 0;
        z-index: 2;
        right: 18px;
        border-style: solid;
        border-width: 0 8px 8px 8px;
        border-color: transparent transparent $color-text-base transparent;
    }
}